Rich,

To break-in your TT GP.42 properly, follow [link=http://www.rcuniverse.com/forum/m_1850473/anchors_1850473/mpage_1/key_tapered%252Dbore%252Cbreak%252Din/anchor/tm.htm#1850473]this thread[/link] closely.

Any other tapered-bore (without a piston ring) engine must be similarly treated, to achieve the best power and reliability and the longest possible service life.